This work proposes a push-push double feedback oscillator (DFBO) topology, which is able to reduce the parasitic capacitance of the transistor, and satisfy the condition for maximum power at fundamental (f o ) and 2 ndharmonic (2f o ) frequencies simultaneously, thus maximizing the oscillator output power. Oscillators adopting the proposed topology are implemented in a 65-nm CMOS, and the measurements show the maximum output powers of 5.0 and −3.9 dBm with maximum DC-to-RF efficiencies of 2.94 and 0.58 % at operating frequencies of 293 and 440 GHz, respectively.